Genus Petrochirus Stimpson, 1858

Type species. Cancer diogenes Linnaeus, 1758

Diagnosis. Fourteen pairs of gills with entire lamellae. Rostrum small, rounded, at level of lateral projections. Ocular peduncles slender; ocular scale separated. Antennal flagella with very short setae. Ischium of third maxillipeds with well developed crista dentata. Right cheliped stronger than left. Males with 4 unpaired pleopods (pl2–pl5) with inner ramus rudimentary. Females with 3 unpaired pleopods triramous (pl2–pl4), pl5 very small, with inner ramus rudimentary.